<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Mysql.php 16942 2009-07-22 04:03:09Z ralph $
 */


/**
 * @see Zend_Db_Adapter_Pdo_Abstract
 */
require_once 'Zend/Db/Adapter/Pdo/Abstract.php';


/**
 * Class for connecting to MySQL databases and performing common operations.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Db_Adapter_Pdo_Mysql extends Zend_Db_Adapter_Pdo_Abstract
{

	/**
	 * PDO type.
	 *
	 * @var string
	 */
	protected $_pdoType = 'mysql';

	/**
	 * Keys are UPPERCASE SQL datatypes or the constants
	 * Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE, or Zend_Db::FLOAT_TYPE.
	 *
	 * Values are:
	 * 0 = 32-bit integer
	 * 1 = 64-bit integer
	 * 2 = float or decimal
	 *
	 * @var array Associative array of datatypes to values 0, 1, or 2.
	 */
	protected $_numericDataTypes = array(
	Zend_Db::INT_TYPE    => Zend_Db::INT_TYPE,
	Zend_Db::BIGINT_TYPE => Zend_Db::BIGINT_TYPE,
	Zend_Db::FLOAT_TYPE  => Zend_Db::FLOAT_TYPE,
        'INT'                => Zend_Db::INT_TYPE,
        'INTEGER'            => Zend_Db::INT_TYPE,
        'MEDIUMINT'          => Zend_Db::INT_TYPE,
        'SMALLINT'           => Zend_Db::INT_TYPE,
        'TINYINT'            => Zend_Db::INT_TYPE,
        'BIGINT'             => Zend_Db::BIGINT_TYPE,
        'SERIAL'             => Zend_Db::BIGINT_TYPE,
        'DEC'                => Zend_Db::FLOAT_TYPE,
        'DECIMAL'            => Zend_Db::FLOAT_TYPE,
        'DOUBLE'             => Zend_Db::FLOAT_TYPE,
        'DOUBLE PRECISION'   => Zend_Db::FLOAT_TYPE,
        'FIXED'              => Zend_Db::FLOAT_TYPE,
        'FLOAT'              => Zend_Db::FLOAT_TYPE
	);

	/**
	 * Creates a PDO object and connects to the database.
	 *
	 * @return void
	 * @throws Zend_Db_Adapter_Exception
	 */
	protected function _connect()
	{
		if ($this->_connection) {
			return;
		}

		if (!empty($this->_config['charset'])) {
			$initCommand = "SET NAMES '" . $this->_config['charset'] . "'";
			$this->_config['driver_options'][1002] = $initCommand; // 1002 = PDO::MYSQL_ATTR_INIT_COMMAND
		}

		parent::_connect();
	}

	/**
	 * @return string
	 */
	public function getQuoteIdentifierSymbol()
	{
		return "`";
	}

	/**
	 * Returns a list of the tables in the database.
	 *
	 * @return array
	 */
	public function listTables()
	{
		return $this->fetchCol('SHOW TABLES');
	}

	/**
	 * Returns the column descriptions for a table.
	 *
	 * The return value is an associative array keyed by the column name,
	 * as returned by the RDBMS.
	 *
	 * The value of each array element is an associative array
	 * with the following keys:
	 *
	 * SCHEMA_NAME      => string; name of database or schema
	 * TABLE_NAME       => string;
	 * COLUMN_NAME      => string; column name
	 * COLUMN_POSITION  => number; ordinal position of column in table
	 * DATA_TYPE        => string; SQL datatype name of column
	 * DEFAULT          => string; default expression of column, null if none
	 * NULLABLE         => boolean; true if column can have nulls
	 * LENGTH           => number; length of CHAR/VARCHAR
	 * SCALE            => number; scale of NUMERIC/DECIMAL
	 * PRECISION        => number; precision of NUMERIC/DECIMAL
	 * UNSIGNED         => boolean; unsigned property of an integer type
	 * PRIMARY          => boolean; true if column is part of the primary key
	 * PRIMARY_POSITION => integer; position of column in primary key
	 * IDENTITY         => integer; true if column is auto-generated with unique values
	 *
	 * @param string $tableName
	 * @param string $schemaName OPTIONAL
	 * @return array
	 */
	public function describeTable($tableName, $schemaName = null)
	{
		// @todo  use INFORMATION_SCHEMA someday when MySQL's
		// implementation has reasonably good performance and
		// the version with this improvement is in wide use.

		if ($schemaName) {
			$sql = 'DESCRIBE ' . $this->quoteIdentifier("$schemaName.$tableName", true);
		} else {
			$sql = 'DESCRIBE ' . $this->quoteIdentifier($tableName, true);
		}
		$stmt = $this->query($sql);

		// Use FETCH_NUM so we are not dependent on the CASE attribute of the PDO connection
		$result = $stmt->fetchAll(Zend_Db::FETCH_NUM);

		$field   = 0;
		$type    = 1;
		$null    = 2;
		$key     = 3;
		$default = 4;
		$extra   = 5;

		$desc = array();
		$i = 1;
		$p = 1;
		foreach ($result as $row) {
			list($length, $scale, $precision, $unsigned, $primary, $primaryPosition, $identity)
			= array(null, null, null, null, false, null, false);
			if (preg_match('/unsigned/', $row[$type])) {
				$unsigned = true;
			}
			if (preg_match('/^((?:var)?char)\((\d+)\)/', $row[$type], $matches)) {
				$row[$type] = $matches[1];
				$length = $matches[2];
			} else if (preg_match('/^decimal\((\d+),(\d+)\)/', $row[$type], $matches)) {
				$row[$type] = 'decimal';
				$precision = $matches[1];
				$scale = $matches[2];
			} else if (preg_match('/^float\((\d+),(\d+)\)/', $row[$type], $matches)) {
				$row[$type] = 'float';
				$precision = $matches[1];
				$scale = $matches[2];
			} else if (preg_match('/^((?:big|medium|small|tiny)?int)\((\d+)\)/', $row[$type], $matches)) {
				$row[$type] = $matches[1];
				// The optional argument of a MySQL int type is not precision
				// or length; it is only a hint for display width.
			}
			if (strtoupper($row[$key]) == 'PRI') {
				$primary = true;
				$primaryPosition = $p;
				if ($row[$extra] == 'auto_increment') {
					$identity = true;
				} else {
					$identity = false;
				}
				++$p;
			}
			$desc[$this->foldCase($row[$field])] = array(
                'SCHEMA_NAME'      => null, // @todo
                'TABLE_NAME'       => $this->foldCase($tableName),
                'COLUMN_NAME'      => $this->foldCase($row[$field]),
                'COLUMN_POSITION'  => $i,
                'DATA_TYPE'        => $row[$type],
                'DEFAULT'          => $row[$default],
                'NULLABLE'         => (bool) ($row[$null] == 'YES'),
                'LENGTH'           => $length,
                'SCALE'            => $scale,
                'PRECISION'        => $precision,
                'UNSIGNED'         => $unsigned,
                'PRIMARY'          => $primary,
                'PRIMARY_POSITION' => $primaryPosition,
                'IDENTITY'         => $identity
			);
			++$i;
		}
		return $desc;
	}

	/**
	 * Adds an adapter-specific LIMIT clause to the SELECT statement.
	 *
	 * @param  string $sql
	 * @param  integer $count
	 * @param  integer $offset OPTIONAL
	 * @throws Zend_Db_Adapter_Exception
	 * @return string
	 */
	public function limit($sql, $count, $offset = 0)
	{
		$count = intval($count);
		if ($count <= 0) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("LIMIT argument count=$count is not valid");
		}

		$offset = intval($offset);
		if ($offset < 0) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("LIMIT argument offset=$offset is not valid");
		}

		$sql .= " LIMIT $count";
		if ($offset > 0) {
			$sql .= " OFFSET $offset";
		}

		return $sql;
	}

}
